I like the charm this game has. the music, the graphics, and the story
but I noticed some of the flaws in your game that make me so frustrated
first, The hitbox :
right now, I think this is the hitbox(or collision box) for this game
This makes sense for the sprites but this makes actual gameplay seems unfair.
for example, this count as collided
most games have smaller hitboxes then they appear to make it more fairer to players :
next, the movement
As the mastergammler said, the controls are too 'floaty'.
it's pretty awesome to see some physics stuff like a momentum, acceleration things like that but I think it doesn't fit too well in this game and wished it was toned it down a bit.
And beating the boss( the final chapter ) felt like it was just luck than my skill and the first part reminded me of the Getting over it.
still, I really like the awesome music, cute and simple graphics and the story and like how each chapter has it's own gameplay mechanics, it's really cool that you made it in 10 days. it took me about 45 minutes to beat this game on my first playthrough, just with some more polish this could be a very fun game!
Nice job!
minor thing, you can just skip chapter 1 by just going straight from the bottom of the screen.